Let's take an example. An enterprise is has a multicast application
with IPv4, for example, video broadcast of CEO talking every morning
:-), delivering stock prices to the brokers' terminals, or whatever.
(Videoconferencing is out of scope.) Those are mainly one-to-many multicast.
I think you mean "single sender" since all multicast is "one-to-many". Are you explicitly excluding applications, such a streaming media, which have a unicast feedback channel? (for quality reports etc)
I'm not sure that "single sender" would be correct in all cases either, since the encapsulator could occur on an IPv6 router (or some other middlebox) which might be many IPv6 routing hops down the line from the original source(s) - of which there could be many.
Fred ftemplin@iprg.nokia.com